Die button



United States Patent O 3282143 DIE BUT'IIUN Hans W. Wierseheim, Norwallls, (Pinie, assignmr to Knhl= man Maehine Company, Norwalllk, Ohio 21 corporation of Ohio Fiietl Api. 2, 1964, Sei. N0. 356,862 6 Cllzaims. (CH. 83-680) This invention relates to an improved die button coustruction Which may be used in a punch or blanking press in which removable die buttons are utilized. More speeifically, this invention relates to an improved die button which may be used in existent die sections or die button retainers and which Will prevent damage to the die button retainer when the improved die button becornes packed With slugs of the nietal being punched or when the die button is broken due t misalignment of the punch or other malfunction of the machine.

Punching and blanking presses throughout the industry commonly use replaceable die buttons held in a die section or die button retainer. Interchangeable die buttons are advantageous in manypunching and blanking operations since a number of holes of various sizes or shapes of blanks may be formed 011 a single power press through use of a series of interchangeable punches and die buttons. The die buttons, which rnay be press fit or otherwise seeured Within a die section er die button retainer plate, rnay be easily and e-conomieally replaced When their entting edges have becorne worn and are now -available in many various sizes and shapes throughout the industry.

Still a further advantage in using die buttons in punch o1 blanking p resses in addition to their interchangeability and economy, is the fast that the die buttons themselves, being relatively inexpensive, are frequently the only portion of the die section of the press Which is damaged due to malfunction in the punching '0r blanking o'peration. For instance, if the punch, during a punching operation,

becornes bent 0r otherwise gets out of alignment Wlllh However, in aggravated cases of slug-packing, the

punch may create stresses in the die button Which are transmitted to the die section or die retainer plate holding the die button causing the adjacent areas 0f the die section er die retainer plate to fail. T bis is particularly true in operations requiring high punch forces such as those perforrned on relatively thick materials in which a blank or slug is most likely to be retained Within the die.

lt has been discovered that damage to the die section from slug-packing Within a die button may be prevented by use of an improved die button constructed to absorb stresses and allow breakage 0f the die button without darnage to the adjacent die sections.

Accordingly, it is an object of this invention to provide an improved die button for use in punch and blanking presses which, because of its construction, Will not transrnit breaking stresses to the adjacent surfaces of the die section ordie retainer plate holding it.

It is another object of this invention to provide an improved die button construction which may be used in existing die sections or die retainer plates which has a stress absorbing means to prevent breaking stresses from being transrnitted frorn the punch to the adjacent surfaces of the die retainer plate or die section It is a further object 0f this invention to provide an improved die button which may be press-fit or otherwise 3,282,i43 Patentecl Nov. l, 196

'ice

secured Within a conventional die button retainer or die section and which will prevent breaking stresses from being transmitted fron1 the punch through the die button to the adjacent surfaces of the die button retainer or die section when the punch is out of alignment with the die button o1 when the die button becomes packed with slugs or blanks.

Other objects and advantages of this invention will be apparent from the following specification and drawings in which:

FIG. 1 is a view in perspective of an improved die button of this invention;

FIG. 2 is a plan view of the die button shown in FIG. l;

FIG. 3 is a cross sectional view in elevation, taken along the line 3-3 of FIG. 2, showing the -construction of the improved die button; and

FIG. 4 is a schematic view in cross section showing the improved die button of this invention press-fit in a die section or die retainer and showing the position of a cooperating punch axially aligned above the improved die button.

FIG. 1 shows an improved die -button of this invention which generally com-prises a cylindrical body 19 having an axially extending punch hole 11 throughout its length. The punch hole 111 is of eourse, the size and shape as dete.rrnined by the size of the blank 0r hole to be punehed in the punching operation The puneh hole 11 is slightly langer in diameter than the diameter of the punch 12, shown in FIG. 4, which, when forced against the upper surface of the blank 13, causes the blank 13 to shear between the ed-ge 14 of the punch and the edge 15 of the die -button forclng a slug of. material through the punch hole 11 in the die button.

As seen in FIGS. 3 and 4, the lower portion of the punch hole 11 is outwardly flaxed t0 provide a radially relieved zone, generally designated by the reference numeral 16, which gives additional clearance for the sing to drop through the die button after it has been pushed past the up-per -*part of the punch hole 11.

Dies and die buttons having radially relieved punch holes are well known in the a1t. However, due to the fact that the dies and die buttons must withstand cousiderable stress upon the =cutting edges 15 in a direction parallel with the inovement of the puncn (se-e FIG. 4), it is impractical to flare or relieve the punch hole 11 in the die button throughout its length, since the cuttin-g edge 15 must have suflicient support immediately below the upper snrface 17 of the die or die button. Therefore, the punch hole 11 must have uniform cross section for a substantial lengtn of the die button, as illustrated in FEGS. 3 and 4. Due to this necessity of maintaining the uniform Cross section of the punch hole 11 throughout a substantial length of the die button, the problern of jamming or pa-cking of slugs or blanks Within the upper portion of the die or die button persists. As shown in EKG. 3, a slug 18 may become cocked or wedged within the upper po.rtions of the punch hole 11. When this occurs, the punch 12, 011 its next downward stroke Will strike the slug 13 and, depending upon the size of the sing 18 and the manner in wl1ich it is jammed in the narrow portion of the punch hole 11, Will either push the slug 18 out of the die button or further impact it, leaving a second slug on top of it. If a nurnber ofirnpacted slugs 18 build up within the die button, er if the -metal being worked is relatively heav a subsequent stroke oftl1e punch 12 will transrnit suflicient force through the slug 18 to crack the die button, distort it 0r bend the punch 12. Once the die button has beeome distored 01 misaligned with the punch 12, subsequent strokes of the puneh 12 will result in .its eutting edges ]l4 striking the npper surface 17 of the die bntton and will injnre the pnnch 12 as weil as the die bntton.

As shown in FIG. 4, the die bnttons, which are pressfit or securely heid Within the die section o1 die retainer 19 and backing piate 20, Will transmit the pressures from the punch 12 and, in many case, canse injury to the die section or die retaine.r 19. When working with materials requiring reiatively iarge pnnching force, the die bntton will transrnit sufficient force frorn the pnnch 12 throngh the jammed sing 18 to crack adjacent areas of the die section 19. If the die seetion 19 has an npwardiy extending boss 21, as shown in FIG. 4, this boss 21 is i.ikeiy to be fractnred along with the npper areas of the die bntton. As previonsly expiained, the die sections 19 are reiatively expensive in comparison with the smaiier die buttons and reqnire more tirne to replace, when fractnred as described above.

Accordingly, in the improved die button of this invention, a resiiient annniar band 22 is circumjacent the npper portion of the cylindricai body 10 of the die bntton as shown in FIGS. 3 and 4. The body 10 cf the die button has an npper portion 23 of reduced diameter and a land 24 which snpports the res.iiient band 22 as best shown in FIGS. 1, 3, and 4. The resiiient band 22, which may be made of any resilient material such as hard rubber, Teflon, or other resiiient synthetic resinons materials, is pressfit or adhesiveiy secnred around the upper portion 23 cf the die button.

The pnrpose of the resiiient band 22 around the upper portion 23 of the die button is to abso.rb the force transmitted frorn the punch 12 throngh the sing 18 to the Wall of the npper portion 23 of the die button and prevent this force from cracking the boss 21 or adjacent area of the die retainer 19. As ilinstrated in FIG. 3, a sing 18, which becomes cocked within the punch hole 11, upon the next stroke of the puneh 12, will transmit lateral force to the wali of the npper portion 23 of ihe die bntton, and, pamticulariy if the sing 18 .is of a relativeiy heavy materiai, will dig in at its edge 25 and crack the wali f the npper portion 23 of the die bntton in the area ind.icated by reference nnmbe.r 26. As soon as the wail of the upper portion 23 of the die button is fractured, the lateral force exerted by the impacted sing 18 will cause the broken section of the die button to siightiy compress the resiiient band 22. As the resiiient band 22 is compressed, the slight radiaily outward movement of the broken section of the die button will increase the diameter of the punch hole 11 in that area, freeing the impacted sing 18 which is then pushed throngh the die button by the punoh 12. Thus, only a siight amount of compression is required of the resiiient band 22 to release the impacted sing 18 and permit the pnnch 12 to compiete its downward movernent. Although the die button itseif has become dama-ged and mnst be repiaced, the action of the xesiiient band 22 has prevented further darnage to the boss 21 of the more expansive die section 19. The pnnoh press may be quickly repaired by a piacernent of the die bntton only and operation may be resumed. Furthermore, since the siight amonnt of compression by the resiiient band 22 has released the impacted sing 18, subsequent cyoies of the punch 12, prior to .repair, Will not aiiow a number of slngs 18 to be bniit up which may eventuaiiy cause damage to the pnnch 12 itseif, as previonsly expiained. Therefore, the res.iiient band 22 0f the die bntton protects the die section 19 from serious damage and also prevents a bnildnp of impacted siugs 18 which may canse damage to the punch The resiiient band 22 shonid be dimensioned such (hat its outer snrface extends siightiy beyond the outer snrface of the cyiindrical body of the die button, as shown in FIG. 3. This insn.res a snug fit of the entire improved die button within the die retainer or die section 19 since the resiiient band 22 must be slightiy compressed so that its outer surfaces are flnsh with the outer snrfaces of the cyiindrical body 10 when the die bntton is in place, as shown in FIG. 4. The resilient band 22 shonid have an axial length approximateiy equai to the distance f.rom the upper snrface 17 01 the die button to the start of the flared portion 16 of the pnnch hole 11 because tne action of the resiiient band 22 is needed througbout the upper portion of the punch hole 12 where the siugs are most likeiy to become impacted. It is not necessary that the resiiient band 22 extend circnmjacent the flared portion 16 of the punci1 hole 12, since this portion has increased clearance and will not permit siugs 13 to become impacted in the manner shown in FIG. 3.

it is to be understood that this .invention may be adapted to die bnttons of irreguiar outer dimensions and also t0 die buttons for pnnching and bianking irregniar confignrations and =having irregular axiai openings. It will b-e apparent that varions ehanges and modifications will b-e made in the specific details discussed above and as shown in the drawings withont departing from the spirit of the attached ciaims.

What I ciaim is:

1. In a die bntton adapted to be r.igidiy secnred in a punch die section and comprising a body portion, a punch aperture cf preselected diameter axiaiiy extending thronghont said body portion, said apertnre being oi: uniform size from the upper face of said die bulton to a point intermediate said die button and outwardly flaring, radially increasing from said intermediate po.int to the iower face of said die bntton, the improvement comprising an npper body portion of decreased externai size axially extending fron1 said npper face to approximately said intermediate point, and an annniar band of a resiiient materiai ci.rcumjacent said npper body -portion, the radially outer snrface of said band extending siightiy beyond the onter surface of said die bntton.

2. An improved die bntton f0r nse in a punch die secti0n comprising a cylindricai b0dy, an axiai punch aprtnre of preselected size t hroughout said body portion, said aperture having a radiaily increasing, tapered portion extending from a point intermediate the upper and iower faces of said body portion to said iower face, an upper portion of said body of reduced externai diameter extending axiaiiy from said uppe.r face of said body to approximately said intermediate point, and an annniar resiiient band eircnmjacent said upper portion of reduced diameter.

3. An improved die button compr ising a cyiindricai main body portion and an nppe.r cyiindricai body portion cf decreased diameter, an axiai punch aperture extending throughout said die button, said punch aperture having a uniform cross section in said npper body portion and an outwardly tapered, radiaiiy increasing cross section throngh said main body portion, and an annniar resilient washer circnmjacent said upper body portion, the radiaily onter snrface of said res.iiient washer extending slightiy beyond the onter surface of said main body portion.

4. An .improved die bntton adapted t0 be rigidly seenred within a eavity in a die section, said die button comprising a body portion with npper and iower faces and having snbstantially the same outer dimensions as said die section cavity, a pnnch apertnre extending through said body portion, said pnnci1 apertnre being of uniform size at its upper end near said npper face and being outwardly tapered at its iower end near said iower face, a peripherai groove on the onter surface cf said body portion extending axiaiiy frorn said upper face to a point intermediate said upper and iower faces and an annniar band of resilient material within said groove and circumjacent said body portion with the radiaiiy outer surface of said band in contact With the waiis 0f said die section cavity wh'en said die bntton is rigidly secured therein.

5. The improved die button of ciaim 4 wherein said body portion is substantiaiiy cyiindricai.

3,282,143 5 6 6. The improved die button of claim 4 wherein said References Cited by the Examiner radially outer surfaoe of said resilient band, when said UNITED STATES PATENTS die button is not mounted in a die cavity, extends s1ightly beyond the outer surfa-ce of said body portion whereg -by said annuiar band will be compressed in a radially 5 3O71O30 1/1963 Larry inward direction when said die button is -rigidly secured in said cavi y of said die sec i n. ANDREW R. JUHASZ, Primary Examiner. 

1. IN A DIE BUTTON ADAPTED TO BE RIGIDLY SECURED IN A PUNCH DIE SECTION AND COMPRISING A BODY PORTION, A PUNCH APERTURE OF PRESELECTED DIAMETER AXIALLY EXTENDING THROUGHOUT SAID BODY PORTION, SAID APERTURE BEING OF UNIFROM SIZE FROM THE UPPER FACE OF SAID DIE BUTTON TO A POINT INTERMEDIATE SAID DIE BUTTON AND OUTWARDLY FLARING, RADIALLY INCREASING FROM SAID INTERMEDIATE POINT TO THE LOWER FACE OF SAID DIE BUTTON, THE IMPROVEMENT COMPRISING AN UPPER BODY PORTION OF DECREASED EXTERNAL SIZE AXIALLY EXTENDING FROM SAID UPPER FACE TO APPROXIMATELY SAID INTERMEDIATE POINT, AND AN ANNULAR BAND OF A RESILIENT MATERIAL CIRCUMJACENT SAID UPPER BODY PORTION, THE RADIALLY OUTER SURFACE OF SAID BAND EXTENDING SLIGHTLY BEYOND THE OUTER SURFACE OF SAID DIE BUTTON. 